Basically, silver halide black-and-white photographic materials are subjected to black-and-white development, fixation, rinsing, etc., after imagewise exposure; silver halide color photographic materials (hereinafter referred to as color photographic material) are subjected to color development, desilvering, rinsing, stabilizing, etc., after imagewise exposure; and silver halide color reversal photographic materials are subjected to black-and-white development, reversal processing, color development, desilvering, rinsing, stabilizing, etc., after imagewise exposure.
In the color development stage, sensitized silver halide grains are reduced by a color developing agent to form silver, and at the same time, the formed oxidant of the color developing agent is reacted with couplers to form an image dye.
In the desilvering stage subsequent to the development stage, developed silver formed in the development stage is oxidized into a silver salt by a bleaching agent having an oxidative effect (bleaching), and the silver salt and unexposed silver halide are converted into soluble salts by a fixing agent and removed from sensitive layers (fixing). Bleaching and fixing are carried out separately as a bleaching stage and a fixing stage. Alternatively, bleaching and fixing are simultaneously carried out as a bleaching-fixing (blixing) stage. The details of these processing stages are described in James, The Theory of Photographic Process, 4th edition (1977), Research Disclosure No. 17643 pp. 28-29, Ibid No. 18716 p. 651 (left to right columns) and Ibid No. 307105 pp. 880-881.
In addition to the above-described basic processing stage, various auxiliary stages such as a rinse stage, stabilization stage, hardening stage, stop stage, etc. are performed to maintain the photographic and physical quality of a dye image or to maintain stability during processing.
The above mentioned processing stages are normally effected in an automatic developing machine. In recent years, photograhic processing is effected in various places such as large-scale photofinishing laboratories equipped with large-sized automatic developing machine and photo processing shops equipped with small-sized automatic developing machine called mini-laboratory. This has often caused deterioration in processing properties.
One of the main reasons for this trouble is contamination of metallic ions in the processing solution.
Various metallic ions enter into the processing solution through various paths. For example, calcium, magnesium or iron ions or calcium contained in gelatin in the light-sensitive material enter into the processing solution with water to be used in the preparation of the processing solution. When the blix solution splashes, iron chelate incorporated therein enters into its prebath, i.e., development bath. When a film impregnated with the processing solution enters into the subsequent bath, ions contained in the processing solution may contaminate the subsequent bath.
The effects of ions which have entered into the processing solution depend on the kind of ions and the processing solution.
Calcium and magnesium ions which have entered into the developer react with carbonates used as buffer to produce precipitate or sludge which causes clogging of filter in the circulation system in the developing machine or contamination of film. The contamination of the developer with transition metal salts such as iron ion causes decomposition of a p-phenylenediamine color developing agent, black-and-white developing agent such as hydroquinone and monol or preservative such as hydroxylamine and sulfite, which leads to a drastic deterioration of photographic properties.
Further, when transition metal ions such as iron ion enter into a bleaching solution containing hydrogen peroxide or persulfate, they also drastically deteriorate the stability of the bleaching solution, causing problems such as poor bleach.
When a commonly used fixing solution comprising a thiosulfate is contaminated by a transition metal salt, its stability is deteriorated, causing the production of stain or sludge in the solution. This results in clogging of filter in the automatic developing machine which causes a drop in the circulated amount of the solution that leads to poor fixation or stain on the film. This phenomenon in the fixing solution can be seen in the washing water in the rinse stage following the fixing stage. In particular, when the amount of washing water is reduced, the percent exchange of solution in the tank is reduced, extremely facilitating decomposition of thiosulfate called sulfuration or precipitation of silver sulfide.
When these phenomena occur, critical stain often occur on the surface of film.
When a stabilizing solution prepared from hard water containing large amounts of calcium and magnesium is used, these impurities serve as nutriments from which bacteria grow, causing stain in the solution and on the film. Further, when transition metal ions such as iron ion enter into the stabilizing solution, these ions are left in the film, deteriorating the storability of the film after processing.
As has been described, the contamination of the processing solution with metallic ions cause various problems. Thus, it has been keenly desired to provide effective ion hiding agents.
As one of approaches for eliminating these problems, chelating agents for hiding metallic ions have been used. Examples of these chelating agents include aminopolycarboxylic acids (e.g., ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid) as described in JP-B-48-30496 and 44-30232 (the term "JP-B" as used herein means an "examined Japanese patent publication"), organic phosphonic acids as described in JP-A-56-97347 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), JP-B-56-39359 and West German Patent 2,227,639, phosphonocarboxylic acids as described in JP-A-52-102726, 53-42730, 54-121127, 55-126241, and 55-65956, and compounds as described in JP-A-58-195845 and 58-203440, and JP-B-53-40900.
Some of these compounds have been put into practical use. However, the properties of these compounds leave much to be desired. For example, ethylenediaminetetraacetic acid exhibits a high effect of hiding calcium ion, but when incorporated in the developer, it accelerates the decomposition of developing agent or preservative for developing agent in the presence of iron ion, causing deterioration of photographic properties, e.g., drop in image density and increase in fog. Alkylidenediphosphonic acid does not give such an adverse effect even in the presence of iron ion, but when incorporated in a processing solution prepared from hard water containing much calcium ions, it causes the production of a solid matter that causes malfunction of the developing machine.
In recent years, as the demand for environmental protection grows, the replenishment rate of photographic processing solutions has been reduced more and more. Under these circumstances, the retention time of the processing solutions in the developing machine has become longer. Thus, the deterioration of the storability of the film becomes even more remarkable than before. Therefore, it has been desired to develop an excellent novel chelating agent which effectively hides metallic ions accummulated in the processing solutions without causing any troubles.
In the field of processing of color photographic materials, a rapid processing service has been provided for customers with the spread of mini-laboratory.
However, ferric complexes of ethylenediaminetetraacetic acid which have heretofore been used as bleaching agents in the bleaching or blix stage in the processing of color photographic materials have a basic disadvantage that they have a weak oxidizing power. Despite some improvements such as use of some bleach accelerators (e.g., mercapto compounds as described in U.S. Pat. No. 1,138,842), the target, i.e., rapid bleach cannot be attained.
As bleaching agents for attaining rapid bleach there have been known red prussiate, iron chloride, bromate, etc. However, red prussiate cannot be widely used due to envrionmental protection problems. Iron chloride cannot be widely used due to poor handleability caused by metal corrosion. Bromate cannot be widely used due to solution instability.
Therefore, it has been desired to provide a bleaching agent which exhibits an excellent handleability and attains a rapid bleach without any problems in discharge of waste liquid.
In recent years, as bleaching agents which satisfy these requirements there have been disclosed ferric complexes of 1,3-diaminopropanetetraacetic acid.
However, these bleaching agents are disadvantageous in that they cause bleach fog upon bleach. As an approach for eliminating bleach fog there has been disclosed a method which comprises the incorporation of a buffer in the bleaching solution (e.g., JP-A-1-213657). However, this improvement leaves much to be desired. In particular, when this approach is employed in a rapid processing wherein color development is effected within 3 minutes with a highly active developer, it causes much more bleach fog.
Further, when a processing solution having a bleaching capacity and comprising a ferric complex of 1,3-diaminopropanetetraacetic acid is used, stain becomes more remarkable during storage after processing.
Moreover, when continuous processing is effected with a processing solution having a bleaching capacity and comprising a ferric complex of 1,3-diaminopropanetetraacetic acid, there are caused some problems such as drastic deterioration of desilvering properties and production of precipitate. Thus, it has been desired to provide an alternate novel processing composition having a bleaching capacity and a processing method using the processing composition.